feat: Update to Slack OIDC (#27115)
* feat: Update to Slack OIDC
Update documentation to support the changes to Slack OIDC made here: https://github.com/supabase/auth/pull/1591/files
* chore: update apps/docs/content/guides/auth/social-login/auth-slack.mdx
* chore: fix prettier
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Co-authored-by: Kang Ming <kang.ming1996@gmail.com>
